1. Field of Invention
The present invention relates to a particle migration type display device, to a drive method for the display device, to a drive device, to a display device, and to an electronic device.
2. Description of Related Art
Particle migration type display devices such as the electrophoretic display device taught in Japanese Unexamined Patent Appl. Pub. JP-A-2006-267982 are known from literature. Such electrophoretic display devices cause charged particles (including pigment) to migrate by applying an electric field, and the color that is displayed is determined by the color of the particles that are near the viewing surface of the display or the color of the fluid in which the particles are dispersed. Conventionally, this type of particle migration display device is driven by causing the particles to migrate until a saturation state in which particle migration stops is achieved to display content. An electrophoretic display device, for example, requires approximately two seconds to redraw the display to a saturation state once a display redraw command is applied.
A problem with the conventional method of driving a particle migration type display device such as an electrophoretic display device is that the redraw time is relatively long because of this saturation drive method and the display appears to be slow when the display changes. For example, during the initial configuration of a time device having such a display, when setting the time, setting the world time zone, setting a timer, selecting the 12- or 24-hour time display method, or selecting the pattern and thickness of time markers, the display is changed frequently and yet the user must wait for the electrophoretic display to finish redrawing a current display setting before proceeding the next setting.
By comparison, it takes several tens of milliseconds to redraw the display on a liquid crystal display device as taught in Japanese Unexamined Patent Appl. Pub. JP-A-H08-68875, for example, and this fast response speed means that the user can quickly switch between these different settings. This also means that when the time is displayed the second, which must be redisplayed every second, can also be displayed, and the time can be rapidly advanced to adjust the time by holding a button depressed, for example.
However, because particles must be migrated, response times on a typical particle migration type display device are slow, and response times comparable to an LCD panel display cannot be expected since it is not yet possible to rapidly redraw the particle migration display.